Home Forums Hunting & Shooting AR and Tactical Rifles AR 15 barrel length

I'm looking at complete uppers and trying to decide between 16" and 18" barrel lengths. The rifle will be scoped. I already have an M4. Any reason to not get an 18" barrel?

What’s your intended use? Either can be fine depends on intended use, not a ton of difference. However, make sure you get the mid-length gas system with either. Softer shooting and just runs smoother.

Mark in GA

You said that it’s going be scoped. If close quarters aren’t an issue for you I’d go with an 18” barrel and a rifle length gas tube. A little added velocity and less muzzle blast are a bonus but mostly for the IMO noticeably softer recoil impulse with the longer gas tube.

If you’re looking for more of a defense type rifle 16”.

What kind of barrel contour are you looking at? I like pencil profiles on 16” barrels and a heavier taper for an 18” barrel. I don’t like M4 profiles.

This^^^^

But don't go any heavier than about 32 oz on the barrel; any heavier really is no advantage in any respect & depending on your rail & stock, can get to be really heavy.

If you go 18", look at WOA's fluted SPR................they are excellent barrels at a fair price.

MM

One big advantage of the 18 inch is rifle gas.

No reason to suffer the longer length and not get the softer shooting rifle gas.

I’ve been favoring 16” barrels for over 20 years now but just recently have come to like the 18” CORE barrel I have from Criterion. It has rifle gas and a lighter contour. Shoots smoother, gives better velocity and is easier on the ears.

I plan to get a complete BRN-180 upper. I should have posted that. My apology. Brownells is out of stock right now. I have a M4 size carbine already with flip up steel sights and an EOtec sight. I have a Sightmark Wraith scope to mount on the 180 upper. Since I'm mounting the scope the 18" seems to make more sense from some of the input.
Thanks, Dave

If you are just hunting with it, I find the 18" to be a little easier to maintain muzzle discipline with especially when the stock is collapsed.

18" is quieter than a 16", still very compact, softer shooting (mine have all been rifle gas), and seems to pick up about 100 fps in most loads. I either run short barrels with suppressors or 18's.

I like 18" with no device, basically as short as a 16" with flash hider.

Good point in 5.56mm. But I do have a couple with 16"/flash hider.

I have 20" barrels on my .300 Ham'r (Wilson Combat) and .223 Wylde (White Oak Armament). Both started with 18" barrels but I wanted to try 20", seems to work. No muzzle devices.
Both were essentially for velocity gain, accuracy did not suffer, otherwise I would have changed back. Both were a conversion from Mid-gas to Rifle gas, a slight improvement.

I tried one .458 Socom with an 18" instead of 16", mistake made there was Mid-gas. Had trouble with 300 grain/H110 or heavy bullets and the lower charges of powder, a volume thing I guess. I may try another 18", but it will be Carbine gassed. It runs good at 16", so I'm not putting a priority on this one. It did have a brake but took it off.

I guess you could say "application matters". I tend to prefer 18"/no device and rifle gas.

How's recoil on the 458 without brake?

It's not that bad if I use a sissy-pad, but w/o it, I get bruising. I'm shooting a 405 hardcast at 1550 fps.

I had one guy come in, set up at the bench next to me, then move down one after I fired.

I finally took it off due to noise. You could tell the difference, but fatigue from noise was just about as bad as from recoil, and it's obviously more compact w/o the brake.

With the various 300 grain loads, it just takes longer to bruise. That's more from buttstock design, though.

I would think the recoil ok. Have shot 50 beowulf for years with a max charge and 275 barnes and its just not much recoil to speak of.

The hard checkered buttplate of the AR stocks can bruise though even though recoil is bad.

Granted I don't shoot the heavier bullets as for my purposes there is no need for it. But obviously it may be worse with them. Have never shot more than 350s in ours IIRC>

Nice to know the 458 is about the same. Have always contemplated a 45 can for pistols and swapping the barrel on the 50 to a 45 so the can would be compatable

Suggest, as you are buying, not building, there is not a hill of beans difference in feel of an 18 VS a 16" in a 223. Recoil in a 223 is a joke at best. Performance in velocity about 50 fps. Just get a mid length gas tube with a 1-8 twist. Barrel weight between a 16 and 18" is all of 2 oz. If you reload do get an adjustable gas block so you can change the gas flow, if necessary, with a powder/bullet change. Options are always good, barrels can be shortened but making them grow longer, like other things, is a bit more complicated.

Like Dave, I’m looking hard at piston options. That limits choices a bit, but 18” is a good place to start for something other than a close-quarters combat rifle. The BRN-180 allows a folding stock if you really need short, but don’t want a pistol. They offer .350, .300, and 7.62x39 if 5.56 bores you….

I went with an 18 inch barrel for one reason: I knew I would be using the rifle for hunting way more then CQB. I wanted more speed and less muzzle blast. A short barreled AR is obnoxious to be around for any period of time. handy but loud Mine is also scoped.

Only one AR?

You'll need to fix that.

Yea, I thought the "15" in AR-15 was a suggestion.

Go 16"bbl, you'll be glad you did. I had 18"& 20"bbls, though the difference seems negligable, it's not when you're climbing around the woods. All I own is M4 configured rifles now, no matter the caliber, 223, 7.62x39, 308win, 22lr.